America may be a bit of a mess when it comes to climate policy—though that mess has been surprisingly effective in reducing carbon emissions in recent years—but environmentalists could always look across the Atlantic Ocean to Europe, where greens are green, cars are small and global warming actually matters. Countries like Germany and Spain have led the way in supporting renewable energy, and cities like Amsterdam and Copenhagen put America to shame when it comes to encouraging dense development and carbon-free cycling. But the green jewel was the Emissions Trading Scheme (ETS)—the European-wide carbon market, by far the largest such system in the world. The ETS, launched in 2005, allowed Europe to put a common price on a ton of carbon, which was meant to encourage utilities and factories to reduce carbon emissions in the most efficient way popular. A similar system carbon cap-and-trade system for the U.S. died in the Senate in 2010, and there’s little chance it will be revived any time soon.

But the ETS—and carbon trading more generally—is not doing well, and its problems are taking some of the green shine off of Europe. Since its launch the ETS has struggled, with the price of carbon falling as the 2008 recession and overly generous carbon allowances undercut the market. In the ETS business are given free allowances to emit carbon—too many free allowances mean they don’t need to reduce their carbon emissions much, which erodes the demand for additional carbon allowances on the market and causes the price to drop. Prices fell from 25 euros a ton in 2008 to just 5 euros a ton in February. There was a way to fix this—take 900 million tons of carbon allowances off the market now and reintroduce them in five years time, when policymakers hoped the economy would be stronger and demand would be greater. As anyone who’s taken Econ 101 would know, artificially reducing the supply of carbon allowances in such a drastic way—something called “backloading”— should force the price back up.

But on April 16, the European Parliament surprised observers by voting down the backloading plan. In turn, the European carbon market collapsed, with the price of a carbon allowance falling by more than 40% over the day. “We have reached the stage where the EU ETS has ceased to be an effective environmental policy,” Anthony Hobley, the head of climate change practice at the London law firm Norton Rose, told the New York Times. The ETS is a mess.

Backloading failed because even in very green Europe, economic concerns seemed to trump environmental ones. European Parliamentary members worried that any action that would cause the price of carbon to rise would add to European industry’s already high energy costs. Europe, unlike the U.S., doesn’t have relatively cheap, relatively clean natural gas to help cushion that blow. At the same time, European nations like Germany are rethinking some of their renewable energy policies, concerned by the rising cost of electricity. It looks like a textbook example of what Roger Pielke Jr. calls the “iron law of climate policy“: when climate policy starts to hurt economically, even the greenest states start to back away.

It’s possible that backloading may get a second chance before the European Parliament, and even without a viable carbon market, Europe is still the global leader in climate action. Nor is the ETS the only game in town. California launched its own cap-and-trade system this year—though that’s come under political pressure as well—and Australia has introduced a price on carbon. China may do so as well. But the hope that we may be able to reduce carbon emissions the same way we cut pollutants like sulfur dioxide and nitrous oxide—through a well-run cap-and-trade —seems to be dimming, a victim of its own complexity and a sluggish global economy. That might leave the door open for other policies, including a straight carbon tax, more support for renewables or increases R&D funding for carbon-free power. We could use all three, but carbon markets may be finished. If carbon trading can’t make it in Europe, it can’t make it anywhere.